This disclosure is directed to compatibilized thermoplastic compositions, articles formed therefrom, and their methods of manufacture, and in particular compatibilized thermoplastic compositions with advantageous properties such as improved impact strength, stable color, or low smoke density.
Polycarbonate homopolymers, polycarbonate copolymers, and polyetherimides are useful in a wide variety of applications at least in part because of their good balance of properties, such as moldability, heat resistance and impact properties, among others. Despite extensive research on these materials over the years, there still remains a need in the art for improved thermoplastic compositions that meet increasingly stringent industry standards.
For example, polycarbonates can generate smoke and heat upon burning, which makes them less suitable for applications in mass transportation (aircraft, trains, and ships), as well as in building and construction. Recently, the European Union has approved the introduction of a new harmonized fire standard for rail applications, namely EN-45545, to replace all currently active different standards in each member state, which will become fully active within the next two to three years. This standard will impose stringent requirements on smoke density allowed for materials used in rail interior applications. It is challenging to develop materials that meet stringent smoke density standards in addition to other material requirements. It is particularly challenging to develop materials that meet these requirements and that have good impact properties at the same time.